Hello ,
I can understand the doubt and confusion you are feeling. Knowing in your gut something is not right but never being able to completely know for sure. This was my entire relationship with my exBPD. My gut instincts said she was not being completely honest with me at times, little signs that something was not as she made it seem. I always ended up giving her the benefit of the doubt but those gut instincts never went away.
The brainwashed feeling is known as
gaslighting. It can really mess up your head, causing you to doubt everything. The lying that your husband is doing could be due to many different reasons. With a pwBPD one of the those reasons would be to avoid shame, which could also be the reason why you husband is lying.
What makes you think he suffers from BPD?